220 The Philippine Journal of Science 1915 
ordinary palpation as practiced in the field there is small likeli- 
hood of serious error. 
Gill * believes that the parasite rate is of less value than the 
spleen rate in the measurement of the malaria rate in a com- 
munity. The number of parasites in the blood may be so small 
as to be overlooked, they may be reduced by the use of quinine, 
and the parasite rate varies greatly at different seasons of the 
year. In northern India he found that benign infections reach 
their maximum in June, and the subtertian in the autumn. 
However, while believing that in northern India no definite 
relationship can be expected to exist between spleen and parasite 
rates, he found that where the spleen rate is high the parasite 
rate also tends to be high. 
In the Philippines, where there is much less seasonal change 
than in northern India, we would expect less seasonal variation 
in the parasite rate. We have found some variation in the para- 
site rate of towns examined at different times in the same year 
(Table VI, Nos. 2, 7, 8, 9, 10, 12, 14, 15, 16, and 51), but only 
one town, Lilio (Table VI, No. 9), showed a negative parasite 
rate at one examination and a very considerable rate, 14, at 
another, and in this town the slides were not in perfect condition 
at the first examination. Many of the towns we examined 
showed a spleen index of 0, although these towns, while not 
in a malarious region, were in no way protected from other 
diseases which might cause enlargement of the spleen. Some 
towns which show a parasite index very low, even 0, with a 
high spleen index are in localities where malaria would be 
expected, as Suliaw and Bolhoon. 
While a larger series than ours may be needed to solve this 
question, we believe that a spleen rate over 10 indicates present 
or past malaria in the most, if not all, the communities of the 
Philippines. However, we would not recommend that the ma- 
larial survey of a locality should rest on the spleen examination 
alone. 
The amount of enlargement of the spleen was measured in 
most towns studied. Of 639 examinations where the degree of 
enlargement of the spleen was reckoned, 336, or 52.6 per cent, 
were classed as simple palpable; 8, or 1.3 per cent, as 1 centi- 
meter below the costal border; 105, or 16.4 per cent, as 2 centi- 
meters below; 125, or 19.6 per cent, as 3 centimeters below; 22, 
or 3.4 per cent, as 4 centimeters below, and 48, or 6.7 per cent, 
as at or below the umbilicus. 
* Tbid., 18. 
